In the electrophotographic process, two-component developers are widely used for commercial machines. Quantity of tribo-electric charge on toner is one of the factors to affect image quality for copies. Effects of toner components and size on tribo-charging are important to evaluate electrophotographic developers. In this study, size dependence on toner charge is examined by a modified E-SPART (Electrical Single Particle Aerodynamic Relaxation Time) analyzer based on a laser Doppler velocimetric method for toner particles of styrene-acrylic copolymer in the size region from 6μ m to 10μ m. As a carrier, a polymer coated ferrite type or a non-coated type is used. From the experimental results, charge to mass ratio q/m decreases from 10 μ C at 6.4μ m to 4.6 μ C at 9.5μ m for toner without silica coating and CCA additives and the reverse m/q shows approximately a linear increase with diameter of toner in a two-component developer combined with a coated carrier. In case of a non-coated carrier, the n-th power size dependence on toner charge is shown to be about 2.7 for the toner with silica coating and CCA additives and about 2.2 for the toner without CCA additives. The results are explained to be consistent with prediction from the surface state theory.
Youichi Nakamura, Yutaka Terao, Shigeru Kitakubo, Yasushi Hoshino, "Size Dependence on Toner Charge in Two-Component Developer" in Proc. IS&T Int'l Conf. on Digital Printing Technologies and Digital Fabrication (NIP24), 2008, pp 321 - 324, https://doi.org/10.2352/ISSN.2169-4451.2008.24.1.art00083_1